Desorption and sputtering on solid surfaces by low-energy multicharged ions

Selective Sputtering of Impurity Hydrogen Atoms from a GaN(0001) Surface by Slow Multicharged Ion Impact

“…A common feature in both the figures is that the relative intensity of hydrocarbon ion peaks compared with each proton peak decreases with an increase in the charge state q of the incident ions. This feature is consistent with our previous results of GaN, [6][7][8]10,12) SiC, 11) and Al 12) surfaces; well-defined Si reconstructed surfaces adsorbing hydrogen atoms; 13,14) and thiol self-assembled monolayer surfaces. 15) The sputtering yield or spectrum intensity of protons emitted from the surfaces interacting with highly charged ions has a strong q-dependence of $q a (a ¼ 1:5 { 4).…”

“…Actually, the ASPS process, or ''pure PS'', was successfully demonstrated in my previous experiment. 6,8) On the other hand, in previous studies it was also found that the contribution of kinetic processes to the sputtering process is not negligible, especially when the scattering particles are perfectly neutralized atoms (q à ¼ 0) even in slow ion impact. [6][7][8] However, the details of this mechanism have not been clarified yet.…”

“…6,8) On the other hand, in previous studies it was also found that the contribution of kinetic processes to the sputtering process is not negligible, especially when the scattering particles are perfectly neutralized atoms (q à ¼ 0) even in slow ion impact. [6][7][8] However, the details of this mechanism have not been clarified yet. Because the perfect neutralization of incoming multicharged ions often results from multiple scattering below as well as above the surface, the momentum transfer between incident ions and atoms in bulk may lead to kinetic sputtering.…”

“…The potential sputtering (PS) induced by slow multicharged ion impacts is increasingly attracting attention from this point of view, 5) because of its two features of sitespecific desorption and slight damage to the bulk. [6][7][8][9][10][11][12] The author succeeded in direct observation of PS of protons on the GaN surfaces irradiated with Ar 6þ by a coincidence measurement of scattered Ar þ ions. 7,9) However, the observed PS was not the dominant process because the number of scattered Ar þ ions was only 23% of that of all scattered Ar atoms/ions.…”

“…The detailed experimental setup and procedure in this study are described elsewhere, [6][7][8] and are mentioned only briefly in this paper. Ar qþ ions with charge state q (4, 6, or 8) and kinetic energy E 0 (2:5 Â q keV) were irradiated tangentially onto a GaN(0001) (Ga face) surface at an angle of $10 with respect to the surface.…”